1. Field of the Invention
The present invention relates to an image processor for use in apparatus which process read image data such as facsimile machines, digital copying apparatus and the like, and more specifically relates to an image processor and image processing method used for processing image data comprising a mixture of character sections, photograph sections, and dot sections in one image.
2. Description of the Related Art
In conventional facsimile machines and the like, image processing can be executed which is suitable for text when an entire document is a text document, and image processing can be executed which is suitable for photographs when an entire document is a photographic document. Such image processing is disadvantageous, however, when text and photographs are mixed in the document image of a single sheet document, inasmuch as it is difficult to independently realize image processing for each text section and photograph section.
Japanese Unexamined Patent Application Nos. SHO61-289764 and HEI3-126180 disclose conventional technology for eliminating the previously described disadvantages. These patent applications disclose processes for discriminating text sections and photographic sections of a document beforehand, and selectively processing image regions having similar attributes simultaneously so as to realize independent processing of text and photographs contained in the document image of a single document sheet.
The subject of Japanese Unexamined Patent Application No. SHO61-289764 relates to facsimile apparatus, and the image data processed are binary data. The region extraction is accomplished using the binary data run length (lines of white picture elements or black picture elements). Japanese Unexamined Patent Application No. HEI3-126180 binarizes input image data, and extracts image regions having similar attributes from among said binarized image data as square-shapes circumscribing said regions.
However, the aforesaid conventional technologies are disadvantageous inasmuch as a long time is required for processing and large-capacity memory is also required because the data processed whenever extracting regions and discriminating attributes are picture element data for the entire document image.
Furthermore, the aforesaid conventional technologies both are only capable of handling rectangular and square regions extracted by attributes.